Opened 18 months ago

Closed 6 months ago

#31320 closed defect (fixed)

Coercion issue with Laurent polynomial rings

Reported by: mmezzarobba Owned by:
Priority: major Milestone: sage-9.6
Component: coercion Keywords:
Cc: Merged in:
Authors: Frédéric Chapoton Reviewers: Travis Scrimshaw
Report Upstream: N/A Work issues:
Branch: 8d97f9d (Commits, GitHub, GitLab) Commit: 8d97f9d08e2f7ddfb52b394d50162e7c2f86952c
Dependencies: Stopgaps:

Status badges

Description

sage: coercion_model.common_parent(Frac(QQ['t']), LaurentPolynomialRing(CC,'t'))
Fraction Field of Univariate Polynomial Ring in t over Rational Field

Change History (10)

comment:1 Changed 18 months ago by chapoton

more data

sage: cm = coercion_model
sage: cm.explain(Frac(QQ['t']), LaurentPolynomialRing(CC,'t'))                  
Coercion on right operand via
    Conversion via converter map:
      From: Univariate Laurent Polynomial Ring in t over Complex Field with 53 bits of precision
      To:   Fraction Field of Univariate Polynomial Ring in t over Rational Field
Arithmetic performed after coercions.
Result lives in Fraction Field of Univariate Polynomial Ring in t over Rational Field
Fraction Field of Univariate Polynomial Ring in t over Rational Field

comment:2 Changed 15 months ago by mkoeppe

  • Milestone changed from sage-9.3 to sage-9.4

Moving to 9.4, as 9.3 has been released.

comment:3 Changed 12 months ago by mkoeppe

  • Milestone changed from sage-9.4 to sage-9.5

comment:4 Changed 8 months ago by mkoeppe

  • Milestone changed from sage-9.5 to sage-9.6

comment:5 Changed 6 months ago by chapoton

  • Authors set to Frédéric Chapoton
  • Branch set to u/chapoton/31320
  • Commit set to ed5f0cafbed3741b2e29a5d7972b28066f6713f3
  • Status changed from new to needs_review

New commits:

ed5f0cafix coercion of Laurent into fraction fields

comment:6 Changed 6 months ago by tscrim

  • Reviewers set to Travis Scrimshaw

Subtle, but a good catch. Green bot => positive review.

comment:7 Changed 6 months ago by git

  • Commit changed from ed5f0cafbed3741b2e29a5d7972b28066f6713f3 to 8d97f9d08e2f7ddfb52b394d50162e7c2f86952c

Branch pushed to git repo; I updated commit sha1. New commits:

8d97f9danother fix

comment:8 Changed 6 months ago by chapoton

I had to change the correction, but now the bot is green.

The issue was about the existence of a morphism from Laurent[t]/QQ to Frac(ZZ[t]).

May I switch to positive ?

By the way, thanks a lot for your reviews, Travis. Domo arigato.

comment:9 Changed 6 months ago by tscrim

  • Status changed from needs_review to positive_review

No problem. Thank you for all your work on improving Sage, especially the code and doc polishing.

comment:10 Changed 6 months ago by vbraun

  • Branch changed from u/chapoton/31320 to 8d97f9d08e2f7ddfb52b394d50162e7c2f86952c
  • Resolution set to fixed
  • Status changed from positive_review to closed
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